Collecting and Storing Pollen
Marthaann Mayer, Huntington, New York
With the new ARS Pollen Bank getting into full swing this year many people have raised questions about the method of collecting and storing pollen. Fortunately, the technique is very simple and reports indicate that properly prepared rhododendron pollen will keep for at least three years, probably much longer, when stored in the home freezer at 0° F (-1 7° C), and may keep indefinitely if stored at much lower temperatures. To use frozen pollen simply allow the pollen to warm up and make crosses as usual. Neither sudden warming nor repeated thawing and freezing seem to injure the pollen.
Pollen should be processed in the following manner.
- Collect pollen only from flowers that are just about to open. This will prevent contamination by foreign pollen brought in by insects. It is also important to dip forceps in 50% alcohol (Vodka, undiluted, will substitute for alcohol) to avoid contamination between varieties. Collect only the anthers not the filament to which they are attached.
- Place the anthers from 1-2 flowers in size 0 gelatin capsules. Don't fill capsules more than half full. Capsules that are very large may make working with small-flowered varieties difficult. Capsules may be obtained at most drug stores although in some areas you may
need a prescription to obtain them.
- Capsules should be labeled with string tags glued on with epoxy or by using magic transparent Scotch tape.
- Dry pollen in the capsules in open containers in the refrigerator (not the freezer section) for 3 days - the refrigerator will dry the pollen. Some people prefer to dry the pollen by placing the capsules in a closed jar with some desiccating material at room temperature for a few hours. Place a loose layer of cotton between the desiccant and the capsules. Never put damp pollen directly into the freezer as this may cause the pollen grains to burst.
- Pollen, when dry, should be stored in the freezer in sealed glass jars containing a desiccant, such as calcium chloride or silica gel. Silica gel is available at many nurseries and hobby supply shops as a material for drying flowers. The "Tell-Tale" type has dark blue crystals that turn pink as they absorb moisture. It can be dried out for re-use by placing it in a 300° oven for a few hours.
- Capsules of pollen for the Pollen Bank should be dried and packed in cotton in a water-proof, crush-proof container, such as a 35mm film can and sent to Marthaann Mayer, Huntington, New York.